A provider of email services (which may be referred to herein as an “email service provider” or an “ESP”) may process email messages on behalf of many customers (which might also be referred to herein as “senders”) and forward the messages to specified recipients over the Internet. These email messages may be sent across the Internet through a number of mail servers operating in the ESP's email delivery system, depending on the volume of email messages being processed and the capacity of the mail servers. The mail servers may utilize the domain name system (“DNS”) to identify the remote mail system designated for a recipient's email address, and then utilize an email protocol, such as the Simple Mail Transfer Protocol (“SMTP”) to forward the email message to the destination mail system. The destination mail system may provide an email inbox to each recipient through which the recipient can retrieve the transmitted email messages. Accordingly, operators of such systems may be referred to herein as “mailbox providers.”
In order to protect recipients from unsolicited junk or bulk email (which may be referred to herein as “spam” or “UBE”), mailbox providers commonly incorporate a variety of known anti-spam techniques to identify and mark such emails. Each email message received by a mailbox provider may be identified by both the sender's email address as well as a source address, such as the Internet protocol (“IP”) address of the mail server within the ESP's email delivery system from which is was sent. As part of the implemented anti-spam techniques, upon detecting a threshold number of email messages identified as spam email, the remote mail system may begin to mark all email from the sending mail server as spam email based on the IP address from which the email message was transmitted. The mailbox providers might also take other types of action, such as slowing down the delivery of email, in response to detecting a high volume of spam email or customer complaints.
Ultimately, a mailbox provider may begin to block all email messages transmitted from a mail server using a particular IP address. In addition, the mailbox provider may share the IP address of the offending mail server with other remote mail systems through the use of a “blacklist.” Consequently, messages transmitted using a blacklisted IP address may be blocked by multiple mailbox providers. This, of course, can be very frustrating for senders of email messages, especially those senders that were not responsible for the blocking of messages by the mailbox providers.
It is with respect to these and other considerations that the disclosure made herein is presented.